Self gain aligning circuit and method

摘要

An K-band amplifier circuit (10) with two samplers (12, 18) coupled to detectors (22, 26) that detect an input and an output RF signal level. These two reference signals are provided to a differential gain control circuit (24) which is coupled to one or more variable gain amplifier (VGA) (14) stages. The VGAs compensate for the gain of an entire chain of amplifiers (16). When the individual amplifier gains vary for any reason, (i.e., process, temperature effects or end of life degradation) the variation in gain causes higher or lower levels of detected output reference signals for a given RF input signal. The gain control circuit (24) drives the VGA (14) up or down as appropriate. By maintaining a constant offset in input and output reference control signals, the gain control circuit (24) drives the amplifier chain (16) to a constant gain.